Method and apparatus for insuring the integrity of vehicle testing procedures

Abstract

A method and apparatus for improving the integrity of a vehicle test procedure insures that the vehicle to which a varying test parameter is applied is the same as the vehicle whose response is required. A random variation to the test parameter is introduced, and the response of a chosen vehicle characteristic to the variation is monitored and correlated with the variations. A high correlation confirms that the vehicle whose response is being monitored is in fact the vehicle to which the parameter is applied. The method may advantageously be used in connection with EPA-sanctioned exhaust emission test protocols.

I claim: 
     
       1. A method for improving the integrity of a vehicle emissions test performed on a test apparatus having means for applying a varying test parameter to a vehicle under test and means for collecting an exhaust sample and determining the concentration of an exhaust constituent in response thereto, by determining if said test parameter applying means and said collecting means are associated with the same vehicle, comprising the steps of: applying a random variation to the test parameter during a test;   monitoring a selected exhaust constituent for a change in concentration associated with said variation;   comparing said change to a standard representing a high level of correlation; and   determining whether the degree of similarity between said change and said standard indicate that the variation was applied to the same vehicle whose exhaust constituent was monitored.   
     
     
       2. The method of claim 1, wherein said varying test parameter is dynamometer engine load. 
     
     
       3. The method of claim 2 wherein said exhaust constituent is hydrocarbon concentration. 
     
     
       4. The method of claim 1 wherein the test comprises pre-test and test portions, wherein said random variation is applied during said pre-test portion. 
     
     
       5. A method for improving the integrity of a vehicle test protocol performed on a test apparatus having means for applying a varying test parameter to a vehicle under test and means for monitoring vehicle performance characteristic in response thereto, by determining if said test parameter applying means and said monitoring means are associated with the same vehicle, comprising the steps of: applying a random variation to the test parameter during a test;   monitoring the performance characteristic for a change associated with said variation;   comparing said change to a standard representing a high level of correlation; and   determining whether the degree of similarity between said change and said standard indicates that the variation was applied to the same vehicle whose characteristic was monitored.   
     
     
       6. An apparatus for improving the integrity of a vehicle test protocol performed on a test apparatus having means for applying a varying test parameter to a vehicle under test and means for monitoring a vehicle performance characteristic in response thereto; comprising: means for applying a random variation to the test parameter during a test;   means for monitoring the vehicle performance characteristic for a change associated with said variation;   means for comparing said change to a standard representing a high level of correlation; and   means for determining whether the degree of similarity between said change and said standard indicates that the variation was applied to the same vehicle whose characteristic was monitored.   
     
     
       7. The apparatus of claim 6, wherein said vehicle performance characteristic is the concentration of an exhaust constituent.